Cancer is a complex and heterogeneous disease, and cancer cells dynamically interact with the mechanical microenvironment such as hydrostatic pressure, fluid shear, and interstitial flow. These factors play an essential role in cell fate and circulating tumor cell heterogeneity, and can influence the cellular phenotype. In this study, a peristaltic continuous flow reactor is designed and applied to HCT-116 colorectal carcinoma cells to mimic the fluid dynamics of circulation. With this intervention, a CD44/CD24-cell subpopulation emerges, and 100 genes are significantly regulated. The expression of cells at 4 h in the flow reactor is very similar to TGF-s treatment, which is an inducer of epithelial-mesenchymal transition. ATF3 and SERPINE1 are significantly upregulated in these groups, suggesting that the mesenchymal transition is induced through this signaling pathway. This flow reactor model is satisfactory on its own to reprogram colorectal cancer cells toward a more mesenchymal niche mimicking circulation of the blood.

A Circulating Bioreactor Reprograms Cancer Cells Toward a More Mesenchymal Niche

The aim of this study was to discuss HIF-1α expression and vasculogenic mimicry (VM) in hepatocellular carcinoma (HCC) and their relationship with the clinical pathological features and clinical significance. Two hundred and seven specimens from patients in The Affiliated Hospital of North Sichuan Medical College who received hepatic cell carcinoma resection were tested by immunohistochemistry and double staining of CD31 and PSA. Then detected the expression of HIF-1α, VM, and analysed the relationship between clinical pathology. The HIF-1α positive rate was 71.01% and its expression was associated with liver cirrhosis, tumor size and TNM stage (P < 0.05). HIF-1α protein expression was positively associated with the VM (γ = 0.1988, P = 0.0041). Hypoxia may be the reason for VM in high invasive HCC, regulating the tumor microenvironment may have great significance in inhibiting invasion and metastasis of HCC.

Expression of HIF-1α in hepatocellular carcinoma and its relationship with vasculogenic mimicry and clinical pathology

Objective: To generate tumor spheres from colorectal cancer cell line HCT116 in serum-free medium (SFM) and to observe the location of the cancer stem cell surface marker CD133 as well as the ratio of CD133+ cells so as to investigate the possible relationship between the epithelial-mesenchymal transition and metastatic ability of tumor spheres. Methods: Human HCT116 colorectal cancer cells were cultured in SFM supplemented with cell growth factors. The location of cancer stem cell marker CD133 in tumor spheres was observed by confocal laser scanning microscopy, and the content of CD133+ cells in tumor spheres was detected by flow cytometry (FCM). Transwell chamber assay, immunofluorescence and reverse transcription polymerase chain reaction (RT-PCR) were applied to examine the metastatic ability of tumor spheres in vitro and the expressions of epithelial-mesenchymal-related key markers. Results: The surface marker CD133 was located on cell membrane, and the content of CD133+ cells was significantly increased in HCT116 tumor spheres. The expressions of mesenchymal markers N-cadherin and Vimentin were highly elevated, while the expression of epithelial marker E-cadherin was reduced. The metastatic ability of cell sphere was higher than that of monolayer cells. Conclusion: HCT116 tumor spheres are enriched with CD133+ cells. The surface marker CD133 is located on the cell membrane. The cell spheres may get higher metastatic ability through epithelial-mesenchymal transition. DOI:10.3781/j.issn.1000-7431.2011.11.004

Metastasis-related characteristics of tumor spheres derived from human colorectal cancer cell line HCT116

Objective: To investigate the effect of long-term exposure to hypoxia on the proliferation of colon cancer SW480 and HCT116 cells, and to explore its possible mechanism.  Methods: SW480 and HCT116 cells were cultured under hypoxic conditions for 14-28 days in vitro. The changes of proliferative ablilities of SW480 and HCT116 cells were detected by MTT method and colony formation assay. The expressions of HIF-1α (hypoxia-inducible factor 1α) and β-catenin—Wnt/β-catenin signalling pathway-associated key factor were observed under a LSCM (laser scanning confocal microscope). The expression levels of HIF-1α, β-catenin, GSK-3β (glycogen synthase kinase-3β), pGSK-3β (Ser9) (phosphorylation of GSK-3β on the Ser9 residue) and PCNA (proliferating cell nuclear antigen) proteins were detected by Western blotting. The results from these detection methods were compared with those obtained from W480 and HCT116 cells exposed to normoxic conditions. Results: The results of MTT method and colony formation assay revealed that the SW480 and HCT116 cells exposed to hypoxic conditions for 2 weeks had higher proliferative ablilities as compared with the cells exposed to normoxic conditions (P < 0.01). The result of LSCM showed that the subcellular localization of HIF-1α expression was changed. Western blotting result revealed that the expressions of HIF-1α (P < 0.05), β-catenin (P < 0.05) and pGSK-3β (Ser9) (P < 0.01) proteins of SW480 and HCT116 cells exposed to hypoxic conditions were increased as compared with the cells exposed to normoxic conditions, but the overall expression of GSK-3β did not change. The expression level of PCNA was increased after exposure to normoxic conditions (exposure to hypoxic conditions vs exposure to normoxic conditions; SW480 cells, P < 0.05; HCT116 cells, P < 0.01). Conclusion: Adaptation to hypoxia may promote the proliferative ability of colon cancer SW480 and HCT116 cell lines and it maybe the result of HIF-1α’s interaction with Wnt/β-catenin signalling pathway. DOI:10.3781/j.issn.1000-7431.2013.01.007

Xiao-ding Yang

Papers

Metastasis-related characteristics of tumor spheres derived from human colorectal cancer cell line HCT116

Effect of long-term exposure to hypoxia on the proliferation of colon cancer cells in vitro